Embodiments of the invention relate generally to electronic power conversion and, more particularly, to a system and method for performing a power conversion on the power output from hybrid DC energy sources, such as a photovoltaic (PV) module and a battery, that allows for the output of the two DC sources to connect to a common DC distribution system.
In industry, it is becoming increasingly common for varying types of energy or power sources to be employed in combination with one another for purposes of power generation and/or distribution. One common example is the use of photovoltaic (PV) systems in combination with DC batteries. PV systems include PV modules arranged in arrays that generate direct current (DC) power, with the magnitude of DC current being dependent on solar irradiation and the magnitude of DC voltage dependent on ambient and solar cell temperature. The use of DC batteries in conjunction with PV systems is often desirable, as the DC batteries provide for energy storage that allows for a number of features that enhance power system operation and enable higher penetration of solar power, while providing a backup source of power during times when solar irradiation is low or absent (e.g., at night).
However, it is recognized that systems that incorporate both PV systems and DC batteries face restrictions with respect to sharing of the DC power—as such sharing of DC power on a common DC bus may not be possible due to the mismatch of the operating voltage between the batteries and the PV systems. That is, for PV systems and batteries—as well as with combinations of other alternative power sources—the power source terminal characteristics such as voltage, current, power flow direction, etc., will often vary greatly. While the use of separate specialized voltage converters with each power source may help address the discrepancies in terminal characteristics between the power sources, the use of such converters can add to the overall cost and complexity of the power system and may affect its reliability.
Therefore, it would be desirable to provide a system and a method that enables the use of a mix of different energy sources (i.e., a hybrid energy system) and that links those energy sources for use in a common system. Such a system and method should provide standardized and flexible conversion or interface circuits to link those energy sources, so as to provide flexible, highly efficient, bi-directional power flow at a lower cost.